I don't think the gear is what you NEED to make the build works, it's just optimal choices(in some cases like the unique belt) or endgame choices. A lot of builds actually work just fine even if you don't trade, which is weird not to do at some point though, you'll get random dropped orbs and stuff so why not.

I'd say the only really item dependant builds are some extreme melee builds or Righteous Fire builds, most of the rest will work just fine even with crap gear, it just won't be as efficient until you do find better gear though. My EK witch had no items from other chars(well I made another char to get fire trap/zombies/phase run or something like that) and it was never really hard, easier than some other builds even. The only thing you really want is a faster projectile for EK asap but that can be done by running a char up to brutus or trading for it, which is fairly cheap.

*my absolute favourite combination. Kaom's for the HP, and to make up for the loss of sockets, the usage of QR which being a dex item will allow you to get the socket colours that you need as well as providing a 100% projectile speed increase which will be absolutely awesome! Can't wait to have someone try this out come OB when Kaom's Hearts get more common due to the increase in population

How good is the projectile speed compared to the spell dmg on a wand/dagger?

So I am playing this build on and off right now as I am trying to hit 60 on my Mara.
So far so good but having major mana issues atm.

Ya that's one of the issues with EK and shadow. My advice is to run 2 hp and 3 mana flasks and stick with EK + Fork till you get better flasks/larger mana pool before going on to use added fire damage. Chain is mainly an end-game option.

*my absolute favourite combination. Kaom's for the HP, and to make up for the loss of sockets, the usage of QR which being a dex item will allow you to get the socket colours that you need as well as providing a 100% projectile speed increase which will be absolutely awesome! Can't wait to have someone try this out come OB when Kaom's Hearts get more common due to the increase in population

How good is the projectile speed compared to the spell dmg on a wand/dagger?

In terms of DPS, spell dmg on wands/daggers will definitely outperform projectile speed, which doesn't affect the tooltip DPS. However, projectile speed is useful because it increases EK range and in this case, a 100% projectile speed will likely double EK's range. Not to mention the fact that having Kaom's Heart will allow a restructuring of the build to decrease the number of HP nodes taken and invest points into more DPS nodes instead while maintaining the survivability of the character. Broadstroke Heavy Quiver should probably be used as well in conjunction with Kaom's and Quill Rain because it increases physical damage by 10%. I should probably add that in as well!